Computer not updating
There was previously no sites configured, and I left the Default-First-Site-Name alone without renaming, but did link some subnets to it. I'm using a catch-all scheme in AD so 10.30.0.0/16 is for all computers in 10.30.1.x, 10.30.2.x, etc...
Authentication seems to be working properly - computers are using DCs based on the IP subnets they are in.
Originally 2003 DCs and so far 1 2008 DC has been added.
Forest functional level is 2000, Domain functional level is 2003.
I found the registry key mentioned in your links and the value matches the same site name that is reported by gpresult.
So, it looks like all computers that were in each site before the subnets/sites were created have updated correctly.
But if I relocate a machine to a different site after Dynamic Site Name key has been created, then it does not update.
The clients are using DHCP and one of the links above explains that locator service looks up the site each time the client IP is leased/renewed. I looked in DNS under _msdcs v_2abhis2 - It is a mixed environment.
Would that allow mobile users (laptops) to always update their site name every time they restart?I could raise the forest to 2003 since there are no more 2000 DCs in the forest, correct?